Investigation of microstructure evolution accounting for crystal plasticity in the multiphase‐field method

Abstract

Regarding microstructured materials, a quantitative prediction of phase transformation processes is highly desirable for a wide range of applications. With respect to polycrstalline materials, the plastic material behavior is commonly investigated using a crystal plasticity (CP) theory, since it accounts for the underlying microstructure, that is, slip systems of the crystal lattice. In classical continuum mechanics, grain boundaries (GBs) are commonly modeled as material singular surfaces. However, the tracking of moving GBs, present during phase transformation processes, is numerically challenging and costly. This can be circumvented by the use of a multiphase‐field method (MPFM), which provides a numerically highly efficient method for the treatment of moving interfaces, considered as diffuse interfaces of finite thickness. In this work, the microstructural evolution is investigated within the MPFM accounting for CP. The implementation of the constitutive material behavior within the diffuse interface region accounts for phase‐specific plastic fields and the jump condition approach. To improve the understanding of the impact of plastic deformation on the phase evolution, a single inclusion problem is analyzed. Within a plastically deformed matrix, the shape evolution of a purely elastic inclusion with a different Young's modulus, referred to as inhomogeneity, is investigated. It is shown, how the anisotropic plastic behavior affects the phase evolution. The resulting equilibrium shapes are illustrated and examined.